
Originally Posted by
bshell
That's true David, but if her perfumes start with 99.9% ethanol, she's going to end up with about 4.4% water after some time, and depending on what's in her perfumes, that could force some things to precipitate out of solution. That's all I'm saying. It actually probably won't happen, but it could happen and then it will be a surprise. I guess she could buy the 99.9% stuff and then leave it open on the counter for a week or two and let it equilibrate and become 95.6% ethanol before using it. That would be a good idea.
Another question so far absent from this discussion is: what is the 0.1% un-named substance in the 99.9% absolute ethanol she is thinking of buying? I.e. what's that missing 0.1%? Is it benzene? That is very likely. I think most people could smell a concentration of 0.1% benzene, don't you?
From the Wikipedia entry on Ethanol:
"Absolute alcohol
Absolute or anhydrous alcohol refers to ethanol with a low water content. There are various grades with maximum water contents ranging from 1% to a few parts per million (ppm) levels. If azeotropic distillation is used to remove water, it will contain trace amounts of the material separation agent (e.g. benzene). Absolute alcohol is not intended for human consumption. Absolute ethanol is used as a solvent for laboratory and industrial applications, where water will react with other chemicals, and as fuel alcohol. Spectroscopic ethanol is an absolute ethanol with a low absorbance in ultraviolet and visible light, fit for use as a solvent in ultraviolet-visible spectroscopy."
To me, this description would be enough to make me avoid buying the 99.9% absolute ethanol material that she is describing.